#define _CRT_SECURE_NO_WARNINGS 1

#include<stdio.h>

int main()
{
    int a = 0;
    int b = 0;
    int c = 0;
    while (scanf("%d%d%d", &a, &b, &c) != EOF)
    {
        if (a + b > c && a - b < c)
        {
            if (a == b || a == c || b == c)
            {
                if (a == b && b == c)
                    printf("Equilateral triangle!\n");
                else
                    printf("Isosceles triangle!\n");
            }
            else
                printf("Ordinary triangle!\n");
        }
        else
            printf("Not a triangle!\n");
    }
    return 0;
}